1. Field of the Invention
The present invention relates to a method of manufacturing a silicon carbide whisker, and more particularly to a method of manufacturing a silicon carbide whisker which is useful as a reinforcing material for various kinds of composite materials.
2. Description of the Prior Art
A silicon carbide whisker is high in strength, has a superior thermal resistance and a resistance to oxidation, and moreover, has low reactivity with metals and has a satisfactory wettability. For these reasons it is used as a raw material for various kinds of composite materials such as fiber reinforced plastics (FRP) and fiber reinforced metals (FRM) through combination with a metal, ceramic, or resin material.
As a method of manufacturing such a silicon carbide fiber, there is known a method by which an organic high molecular silicon compound that has carbon and silicon as its basic structural components, is spun into yarns, sintered, and further given a heating treatment at a high temperature (Japanese Provisional Patent Publication No. 52-70122). However, the method has problems in that its process of manufacture is complicated, control of the temperature for heat treatment is not easy, and a fiber with small diameter is difficult to obtain.
In addition to the above, there are known a method in which silicon is deposited on the surface of a carbon fiber by a vapor phase thermal decomposition method, and then carbon is converted to silicon carbide by sintering it at a high temperature (Japanese Provisional Patent Publication No. 50-38700), and a method in which a mixture of incinerated residue of true grasses and carbon black is treated at a high temperature in a nonoxidizing atmosphere (Japanese Provisional Patent Publication No. 57-209813). However, both methods have problems in that they require a heat treatment at high temperatures, and the purity of the product is low.
Moreover, there is known a method in which a gaseous mixture of a halogen-containing silicon compound and a hydrocarbon is thermally decomposed in a hydrogen atmosphere. However, there were problems in that the method requires a high reaction temperature and also that the whiskers produced are too minute such that the desired physical properties cannot be obtained when they are used for composite materials.